DESCRIPTION: The principal investigator has recently generated mice that lack g-glutamyl transpeptidase (hereafter referred to as GGT), a critical enzyme in the g-glutamy cycle and glutathione metabolism. He now aims to use these GGT- deficient mice for four purposes: 1) to determine why deficient mice lag in growth and sexual maturation; 2) if deficient mice contain other GGT-like activities; 3) to more fully characterize the role of GGT in glutathione and amino acid metabolism; and 4) to examine the role of GGT metabolic pathways in two induced disease states, galactosamine/endotoxin induced liver injury and methylmercury metabolism and toxicity.